21722636 has 24 divisors (see below), whose sum is σ = 41077680. Its totient is φ = 9991872.

The previous prime is 21722629. The next prime is 21722639. The reversal of 21722636 is 63622712.

It is a junction number, because it is equal to n+sod(n) for n = 21722599 and 21722608.

It is not an unprimeable number, because it can be changed into a prime (21722639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21290 + ... + 22286.

It is an arithmetic number, because the mean of its divisors is an integer number (1711570).

Almost surely, 2^21722636 is an apocalyptic number.

21722636 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21722636 is a deficient number, since it is larger than the sum of its proper divisors (19355044).

21722636 is a wasteful number, since it uses less digits than its factorization.

21722636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1433 (or 1431 counting only the distinct ones).

The product of its digits is 6048, while the sum is 29.

The square root of 21722636 is about 4660.7548744812. The cubic root of 21722636 is about 279.0213966795.

The spelling of 21722636 in words is "twenty-one million, seven hundred twenty-two thousand, six hundred thirty-six".